There is no 'Committee for Promotion of Virtue and Prevention of Vice' in Egypt as has been rumoured of late, Yasser Ali, acting spokesman for Egypt's newly-inaugurated President Mohamed Morsi, said on Wednesday.

"It's not true that there is such a committee; the incidents that have happened of late were all instigated by individuals and investigations are still underway," he said.

In the Egyptian canal city of Suez, 22-year-old engineering student Ahmed Said was stabbed to death on Sunday, allegedly by bearded men dressed in galabiyas – attire generally associated with religious Muslims – while walking with his fiancée. He was allegedly assaulted for refusing to divulge his relationship with her to his attackers.

Official Islamist groups have condemned the attacks amid heightened concerns among some quarters about the future of civil liberties in Egypt.

"The law must be strictly brought to bear against any culprits," Ali stressed, referring to purported Islamists who take it upon themselves to enforce 'moral' behaviour.

Initial reports of Saudi-style morality enforcers first began circulating in Egypt earlier this year, when Islamist political forces – mainly the Muslim Brotherhood's Freedom and Justice Party and the Salafist Nour Party – together won some three quarters of the seats in Egypt's parliament.

After months of quiet, the unofficial enforcers appear to have re-emerged recently, shortly after Morsi – a leading Brotherhood figure – won Egypt's first-ever free presidential election.

Apart from the recent Suez incident, several other unconfirmed reports about morality police in Egypt have circulated on the internet.

It has yet to be determined, however, whether the alleged acts of moral policing represent an organised movement or are merely individual acts – or whether they are being perpetrated by parties, as some have suggested, seeking to tarnish the image of political Islam.